1. Field of the Invention
This invention relates to an improved needle for the administration of an anaesthetic agent within the epidural space, and more particularly to a needle tip which minimizes injury to the veins, arteries, nerves and dura of a patient when traversing an area proximate spinal ligaments, such as the ligamentum flavum, to enter a space proximate the dura mater of spinal cord of a patient.
2. Information disclosure statement
Numerous needles are presently in use for effecting an epidural administration of an anaesthetic agent to produce anesthesia. The major disadvantage is the possible penetration of the dura which may result in a severe headache to the recipient-patient.
U.S. Pat. No. 3,782,381 describes a precurved, over the needle catheter with a wing assembly to aid in proper securement of the catheter at the site of the tissue puncture.
U.S. Pat. No. 4,349,023 discloses a device which minimizes kinking of a tubing being inserted through a needle into the eqidural space of a patient.
U.S. Pat. No. 4,518,383 discloses an instrument for eqidural and spinal anesthesia which has an outer assembly and inner assembly. The outer assembly is bent at an angle of about 20.degree. and has an inclined, pointed tip that makes an angle of about 10.degree. with the axis of the instrument. The inner assembly is a hollow needle which extends within the needle of the outer assembly and projects into its forward end. The inner needle also has an inclined, pointed tip that makes an angle of about 30.degree. with the axis of the instrument.
U.S. Pat. No. 4,543,092 discloses a catheter set where the tip of the mandrin includes side facets which are advantageously ground on opposite sides of the tip of the mandrin in order to reduce the wall thickness of the mandrin and the angle of the tip of the mandrin is between 35 and 45 degrees relative the axis of the mandrin.
These devises, however, utilize a sharp needle tip which fails to minimize the damage to the nerves and blood vessels.
U.S. Pat. No. 2,922,420 discloses a blunted epidural needle which utilizes a lateral opening at the tip end.
Epidural anaesthesia is accomplished by using an epidural needle to enter the epidural space. After entering the epidural space the dura mater is encountered. Care must be taken not to penetrate the dura. In the event the dura is penetrated, adverse results, such as a severe headache may occur.
Therefore, it is an object of this invention to provide an epidural needle device which minimizes the damage to the nerves and/or blood vessels through the use of a flat tipped and inclined needle point when entering the epidural space or the space outside the dura mater of the spinal cord thereby increasing the safety of epidural administration while providing for prompt and rapid penetration into the epidural space.
It is a further object of this invention to provide an epidural needle device which does not require a catheter to be inserted into the passageway of the needle to administer a drug into the epidural space.
It is a further object of this invention to provide a needle which injects an anesthetic, or the like, straight from the tip of the needle thereby minimizing loss of anesthetic to surrounding tissue.
It is a further object of this invention to provide an epidural needle device which utilizes a small gauge needle shaft to limit the damage caused by the insertion of the needle device.
It is a further object of this invention to provide a unitary tip which comprises a needle shaft having an axial channel and a solid rod being received into the axial channel such that the tip of the needle and the tip of the solid rod together form a unitary tip which aids in traversing the tissue of a patient.
It is a further object of this invention to provide an epidural needle device which does not require special insertion apparatus.
It is a further object of the invention to provide a needle tip which easily traverses the spinal ligaments to arrive at the epidural space and which minimizes or prevents penetration of the dura and possible further penetration into the subarachnold space which minimizes or prevents the occurance of a headache resulting from penetration of the dura.
The foregoing has outlined some of the more pertinent objects of the present invention. These objects should be construed to be merely illustrative of some of the more pertinent features and applications of the invention. Many other beneficial results can be obtained by applying the disclosed invention in a different manner or modifying the invention within the scope of the disclosure. Accordingly, other objects and a fuller understanding of the invention may be had by referring to the summary of the invention and the detailed description describing the preferred embodiment in addition to the scope of the invention defined by the claims taken in conjunction with the accompanying drawings.